Nearly 40 percent of people with education debt may default on those loans by 2023, according to the think tank’s analysis of Department of Education data. Brookings studied past trends for default rates and projected them over the next five years.

The data indicate that most African-American students who borrow money to attend a for-profit college are putting themselves on the road to eventual default, especially if they didn’t earn a bachelor’s degree. Sixty-seven percent of black dropouts who ever attended a for-profit school are likely to default within 12 years of entering college, Brookings estimated.

Student debt can’t be expunged by filing for bankruptcy, making the loans particularly onerous. Several studies have shown that student debt has forced the millennial generation to delay financial commitments like buying a home or starting a family, a trend that weighed on the broader economy.

“Debt and default among black or African-American college students is at crisis levels, and even a bachelor’s degree is no guarantee of security: black BA [bachelor's degree] graduates default at five times the rate of white BA graduates (21 percent versus 4 percent), and are more likely to default than white dropouts,” Brookings said.

“The results suggest that diffuse concern with rising levels of average debt is misplaced,” according to study author Judith Scott-Clayton. “Rather, the results provide support for robust efforts to regulate the for-profit sector, to improve degree attainment and promote income-contingent loan repayment options for all students, and to more fully address the particular challenges faced by college students of color.”

Students who borrow more money for college than they're able to pay back have multiplied to crisis levels -- and the future is about to get much worse, according to an analysis by the Brookings Institution.